For the LTE standard and as well for the UMTS standard, so-called ANR functionalities (Automatic Neighbor Relationship) have been standardized by the relevant standardization organization (3GPP) to identify and organize neighbor relationships among cells which is the basis for mobility of mobile devices (user equipments) within the mobile communication network or parts thereof.
One basic pre-requisite and assumption for the use of ANR functionalities, but generally also for mobility of user equipments within the mobile communication network, is that cell identification information being assigned, by the operator of the mobile communication network, to a radio cell is unique, and hence it is possible to identify that radio cell, at least on a local level (i.e. not necessarily network-wide) via that identification information. This information is often referred to as the so-called physical cell identifier information or PCI (Physical Cell Identifier): it identifies the radio cell of the mobile communication network as a short identifier but, at least in general, it is not (necessarily) unique regarding the complete mobile communication network (i.e. network-wide).
At the very least, this assumption should be verified—in view of using ANR functionalities—that the pair of values of:                the physical cell identifier information, and        the center frequencyis locally unique in order to be able to identify that radio cell, i.e. on a local level within the mobile communication network (i.e. not necessarily network-wide). As a consequence, it should be possible to unambiguously identify any radio cell via the physical cell identifier information and the center frequency.        
However, due to the fact that the number of possible physical cell identifier values (e.g. 504 different values according to the LTE standard)—as well as the number of possible values of the downlink primary scrambling code (e.g. 512 different values according to the UMTS standard) is limited, and especially in complex network situations, e.g. involving a plurality of network layers, the problem of confusion and/or of conflicts regarding the physical cell identifier information (or downlink primary scrambling code) and/or regarding the pair of values of the physical cell identifier information (or downlink primary scrambling code) and the center frequency (so-called PCI confusions or PCI conflicts) occur, especially in case that a plurality of different frequency bands (such as the LTE800 frequency band and the LTE1800 frequency band) are used, and no neighbor relation planning is performed, e.g. upon or during the deployment of the mobile communication network.
In contrast to the physical cell identifier information assigned to the radio cells of the mobile communication network, the cell global identifier information (also called CGI, Cell Global Identifier) is a unique identifier for a radio cell, i.e. its knowledge enables precisely identifying the radio cell (at least network-wide, if not globally). However, the cell global identifier information is more extensive and coded in a different manner within the signaling data than the physical cell identifier information (typically being “longer”, i.e. comprising a higher number of digits) and, especially due to this property, is not read (i.e. decoded or received), by a standard user equipment, in any case, just for the purposes of normal mobility measurements, i.e. in case that the user equipment detects that the radio link with the serving base station entity becomes weaker (and the radio signals of another base station entity of another radio cell becomes stronger) and hence a handover procedure could be required.
Accordingly, situations of confusion and/or of conflicts regarding the physical cell identifier information (and/or regarding the physical cell identifier information and the center frequency) often result in a reduced level of quality of service provided by the mobile communication network to the respective users of the mobile devices or user equipments, lead to a reduced mobility in the mobile communication network and might end up in a dropped connection of the mobile device or user equipment.
In the context of the so-called self-organized network (SON), ANR (Automatic Neighbor Relationship) functionalities are conducted, according to which measurements are performed such that neighbor relations of radio cells are configured automatically, especially based on measurement results received from user equipments. Typically, the information of the identified neighbor radio cells (their used absolute radio frequency channel number (ARFCN), i.e. their center frequency, their physical cell identifier information, their cell global identifier and the IP-address of the connected eNodeB) are stored in lists, like, a list comprising all external neighbor radio cells (neighbor cell list, NCL) of base station entity or an eNodeB, or on cell level in a neighbored cell relations list/table (NRT). To speed up the handover process, usually the measured pair of the center frequency and the physical cell identifier information (ARFCN/PCI) is compared with the available entries in the NRT-list and/or the NCL-list and a handover is trigged to the matching entry. In the context of the present invention, this matching entry is called the target cell. Generally, based on this method, it is requested that the condition be fulfilled that unique pairs of ARFCN/PCI should be present in such a list or such lists, and, of course, to use also within the own cell (source cell) a PCI which is not used in such a list neither. If these requirements are fulfilled (e.g. due to an already configured neighbor relation NRT of the respective radio cells), the base station entity (or eNodeB) of the source radio cell can distinguish the reported measurements from a user equipment and trigger the handover procedure to the correct target cell. However, this is not the case if a possible (other) target radio cell is also a possible handover candidate (due to geographic and/or radio conditions) but has assigned the same pair of ARFCN/PCI than the another possible target radio cell, e.g. due to the fact that it has not yet been identified by the ANR functionality as a possible neighbor relation.